

Springs · Wilmot
Extension Spring Replacement
One of the springs beside the track is hanging loose at the front end, its pulley dangling, and a length of cable lies slack along the top of the door.
In plain words
Every extension spring should carry a containment cable, and replacement is the moment to make sure yours do. A containment cable runs through the centre of the spring and is anchored at both ends, to the rear hanger and to the bracket at the front of the track. It does no lifting; its purpose is to hold a spring that breaks so the pieces stay on the cable. Many older doors predate this practice, which a home inspection checklist checks for. When springs are replaced, new containment cables are fitted with them, which keeps a broken spring's pieces contained, not the door's weight, balance or safety.
How the visit goesIt is the first hard frost of the year and the door on the old detached garage has stopped halfway, squealing at one pulley. The springs are the ones that came with the door decades ago, orange with rust where they hang near the back wall.
Extension Spring Replacement
How the visit goes


Weighing the door
Extension springs are chosen by the weight they are built to lift, so the door is weighed rather than guessed at. With the opener released and the springs disconnected or slack, the technician lowers the door onto a scale set on the floor under the bottom section and reads the figure. That number, together with the door's height, sets the spring rating and stretch length. The old springs are measured as a cross-check, but the scale wins if the two disagree, because a door can gain weight from new panels, insulation or a cladding added since the springs went on.
Balancing the door by hand
Balance is judged with the opener still disconnected. The technician lowers the door to the floor, then lifts it: it should rise with modest effort, stay put when let go at about waist height, sit steady when fully open, and come down under control rather than dropping. If it sinks, both springs need a little more stretch and each S-hook is moved one hole to take up cable; if it climbs on its own, one hole the other way. Adjustments are always made in pairs, with the door open and clamped again each time, so the two springs stay equal. Two or three rounds usually settle it.
Lubrication that keeps the new set turning
Twice a year, in spring and before winter, a can of garage-door lubricant does most of the maintenance the springs need. Spray a light coat along each extension spring, working from the hanger to the pulley; it slows rust in a damp garage and quiets the coils. Put a drop on each pulley axle and on the bolts through the pulley forks, then on the hinge pins and roller stems. Leave the tracks dry and wipe them clean, since grease there collects grit and stops rollers rolling. Heavy grease and general-purpose oil are avoided on the springs because they hold moisture against the wire. Run the door a few times afterwards to spread the film.
Extension Spring Replacement
In the van
Containment (safety) cables
Extension springs, matched pair
Lag screws and hanger bolts
S-hooks and adjusting clips
Lift cables

Extension Spring Replacement
What affects the quote
Door weight and size
Spring rating follows the door's weight, and a wide insulated door or a wood door takes heavier springs than a light single. Weight and height together set the parts on the quote.
Pulleys that need renewing
Each side has two pulleys, and a wheel worn to a groove or a bearing that has stiffened is replaced with the springs. The quote names how many and which type.
Containment cables to add
A door that never had containment cables gets them with the new springs, along with anchor hardware into the framing. It is a small parts line and a worthwhile one.
What to have ready
- Do the springs run along the tracks beside the door, or is there one spring above the opening?
- Is there a thin cable running through the middle of each spring?
- Is there anything stored beside the tracks or under the springs?
Extension Spring Replacement: questions
QuestionsWhat happens during the visit?
The technician releases the opener, opens the door fully and clamps it so the springs go slack, then inspects springs, pulleys, cables, hangers and containment cables and weighs the door. The old springs come off, a matched pair goes on with containment cables through them, the lift cables are routed over the pulleys and the two sides are set to matching hook positions. The door is balanced by hand, the opener reconnected and its reversing tested with you watching.
Should I try to open the door by hand before the technician arrives?
No need, and it is easier on the door if you leave it. With a spring broken or slack, the door is unbalanced and heavy, and lifting it can let it drop or twist a section in the track. If the door is stuck partway, leave it there and keep people and the car away from the opening. The technician brings clamps and props, and the door is secured before it is moved at all.
What information helps when I call?
Whether the springs run along the tracks or sit above the door; whether one is broken, hanging loose or just looks stretched; whether the door is closed, open or stuck partway and level or crooked; roughly how wide and tall the door is and what it is made of; and whether there is a cable running through each spring. A photo taken from inside with the door closed answers most of that at once.
Related services

- Garage Door Hinge ReplacementThe roller at the top of the second panel is leaning outward and only half of the wheel is still in the track.
- Garage Door Track Repair or ReplacementHalfway up, the door lurches and one roller rides onto the lip of the channel.
- Garage Door Cable ReplacementThe cable has wrapped itself around the shaft above the door instead of sitting on its drum.